Power transmission system



April 11; 1944. w, MATSQN 2,346,175

POWER TRANSMISSION SYSTEM Filed July 3, 1942 p o a4 40 1 3s ammo/mm William U. Mat 5 c: n

Patented Apr. ll, i944 l'lE STA 2,343,175 POWER TRANSMISSION SYSTEM William U. Matson, Arlington, Va.

Application July 3, 1942,

2 Claims.

The invention described herein may be manufactured and used by or for the Government for Serial No. 449,590

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) governmental purposes, without the payment to me of any royalty thereon.

This invention relates to drive systems for selfpowered wheeled vehicles, particularly to those in which the power is transmitted through a differential to a pair of drive wheels.

Many drivers of automotive vehicles have at some time or other found themselves in the annoying predicament of being stuck in a snowdrift, muddy road, or the like, where one driving wheel is resting on such a slippery spot that the coefficient of friction is too low to provide traction, with the result that that wheel spins dissipating all the driving power of the engine, and the vehicle stands still. The characteristics of differentials in general use on automotive vehicles are such that the wheel with no traction spins, and the wheel that has a good coefficient of friction with the road receives no torque.

It is the object of this invention to provide a vehicle drive system in which the spinning wheel may be loaded sufliciently to insure that some of the engine torque will be transmitted to the other whe 1. This is accomplished by means for Such a system is easily adapted to fluid pressure brake systems by the expedient 01! providing valves in the fluid pressure lines to permit blocking the transmission of fluid pressure to those lines which connect the pedal cylinder with the brakes of wheels not spinning. The valves in the conduits to the brakes oi' the driving wheels may be interlocked. so that when one line or conduit is blocked, the other remains open.

The sole figure of the drawing shows a wheeled vehicle diflerential with the driving wheels of the vehicle and a fluid pressure brake system embodying the invention.

Referring to the drawing in detail, a cliiierential frame 2 is shown carrying a gear 4 which is positioned to be driven by a propeller shaft pinion (not shown) in the usual manner. Frame 2 carries the conventional idler gears 6 which mesh with side gears 8 and Hi. Gears t and it are keyed to halves i2 and it, respectively. of he rear axle. Axle halves i2 and it are secured to drive wheels l6 and i8, respectively. in any suitable manner. Each wheel is eouipped with a brake drum 20 and a brake shoe 22. Shoe 22 may be actuated into contact with drum 2G by any suitable means, but preferably by a fluid pressure system consisting of cylinders 25 i not shown in detail), conduits 26, and master brake cylinder 28. Piston 30 of cylinder 28 is adapted to b; actuated by any suitable means such as pedal 3 At any convenient point in-conduits 26 are disposed valves 34 and 36, the actuating rods of which are connected to bell crank 38. erating lever 40 is secured to the bell crank. A

A valve 44 The actuating rod of is disposed in conduit 42 valve 44 is disposed for acturning freely, the operator gradually applies pressure to pedal 32, slowly braking wheel I8. As the torque on wheel l8 increases, more and more of the engine power on that wheel is great enough to turn the wheel. As soon as the vehicle off.

I. claim:

1. In a vehicle drive system, a plurality of wheels some of which are driven wheels, a differential through which power is transmitted to the driven wheels, a brake on each wheel, fluid ressure means for operating the brakes including a master brake cylinder and finid conduits leading from said cylinder directly to all the b akes. a fluid control valve in each of the conduits leading from said cylinder to the brakes of the differentially mounted drive wheels and a fluid control valve in the conduit leading from said cylinder to the other wheels, a manually will be forced to wheel 16, until the engine torque operable device for controlling the valves and arranged to close the valve in one conduit to the brake of one differentially mounted wheel and close the valve of the other conduit, accordingly as aid device is moved in one direction or the other, and connections between the device and the valve controlling the conduit to the other wheels to close said valve regardless of the direction in which said device is moved.

2. In a vehicle drive system, a plurality of wheels some of which are driven wheels, a difierential through which power is transmitted to the driven wheels, a brake on each wheel, fluid pressure means for operating the brakes including a master brake cylinder and fluid conduits leading from said cylinder directly to all the brakes, a fluid control valve in each of the conduits leading from said cylinder to the brakes of the differentially mounted drive wheels, and a fluid control valve in the conduit leading from said cylinder to the other wheels, a manually operable lever, connections between said lever and the valves connecting the conduits leading to the difierentially mounted wheels, which when moved in one direction from normal closes the valve in the conduit to the brake of one differentially mounted wheel and in the other direction closes the valve to the other differentially mounted wheel, operable connections between the lever and a cam device shaped to close the valve in the conduit between the master cylinder and the other wheels regardless of the direction in which the operating lever is moved.

WILLIAM U. MATSON. 

